Cutting the cord: future mobile broadband tech
How internet on the go is going to get much faster
Wireless telephony is undergoing a revolution, with technology and implementation philosophy each holding the other back in turn as the industry struggles towards wireless nirvana.
Engineers have spent the last few decades squeezing more data into the same wireless bandwidth, a process that is deep into the realm of diminishing returns. Meanwhile, regulators are loosening rules about what technologies can be deployed by whom, allowing the engineers to exploit new techniques that are defining the standards that will carry the next few decades.
Mobile telephony was predicated on the ability to make voice calls without wires, but the next generation of wireless standards consider voice calling to be a peripheral function. Instead, data takes central stage. Voice is, after all, just another kind of data. The wireless standards used for telephony today still have a separate channel for voice connections, but LTE (Long-Term Evolution) and WiMax (Worldwide Interoperability for Microwave Access) are both data networks designed to carry broadband data which might incorporate the occasional voice call too - a clear change of focus for the so-called fourth generation (4G) of mobile technologies.
Downloading some history, very slowly
Data was very much an afterthought in the design of the original mobile telephone - the first car phones could be connected to a modem which would squawk down the line at a horribly slow speed. In the UK, tech corporation ICL fitted all its engineers' cars with such modems, and phones to go with them, but it never managed to get a data service working reliably over a network that was ill equipped to handle mission-critical data.
Second-generation technology GSM wasn't a lot better, so wireless data remained something for the desperate specialist despite the launch of Wap (Wireless Application Protocol). Wap promised to deliver the internet on the move, a promise that was made though legendary TV ads that have actually been blamed for killing Wap by setting unrealistic expectations:
There followed a sequence of steps in which the industry repeatedly deluded itself that as soon as data connections could be made slightly faster, users would leap to the wireless internet - and be delighted to pay for it.
In the process of trying to make OFDM more palatable to a non-comms audience, you seem to have missed the real advantage of the technique. The real beauty of OFDM is the flexibility given by so many orthogonal low-bandwidth sub-carriers: you can avoid the problem of frequency-selective fading for one user (mitigating their bad channel) by moving their allocation in the spectrum. This leads to much more efficient usage of spectrum, and better channels for all. It is excellent at adapting to nasty channel conditions in slowly-changing channels*.
I'm not really sure what you're getting at with regards to "solving" the problem of "timing". If you're referring to inter-symbol interference, which is indeed a concern, then OFDM doesn't directly solve this by "putting [chunks] in different frequencies" - but what it does do is ensure that the symbol rate on each individual component frequency is low enough that ISI can be mitigated easily. But if you're referring to interleaving, which does indeed spread "chunks" of data amongst frequencies, then that helps solve a different problem: the issue of losing bursts of data in frequency-specific fades.
On the down side, OFDM really isn't good in channels with a great deal of doppler shift (since it breaks the orthogonality between the sub-carriers) - making it non-ideal for use in fast-moving vehicles, for instance, without specific counter-measures.
8390? shouldnt that be 8310?
Good article, but as this article seems to have a UK slant to it.. the 8310 should have been the phone that was mentioned as being the first with GPRS in the UK. The 8390 was not even the first phone in the US with GPRS, a motorola timeport was, if i remember correctly.
Jobs - because the iPhone wasnt a world first in any area.